1. Field of the Invention
The present invention relates to the fields of organic chemistry and material sciences.
2. Brief Description of Related Technology
The state of the art recognizes numerous methods for the functionalisation of surfaces. Such functionalisations are used in order to modify the material properties of the surfaces in a targeted manner. Such functionalisations should be as durable as possible and allow for a highly defined loading of the surface.
In the field of medical technology, special importance is placed on functionalised surfaces. Implants should—by way of example in the dental industry and orthopedics (joint replacement)—be as biocompatible as possible, i.e. by not, inter alia, having a tendency towards biofouling, not causing any inflammatory reactions and not being seeded with pathogenic microorganisms. Furthermore, they must permanently resist heavy mechanical strain.
Medical implants frequently comprise the metals iron and/or titanium, while dental implants also contain apatite. Until now, monomeric derivatives of the catecholamine have been used as a surface binder to which different functional molecules such as antibiotics or PEG were subsequently bonded. With such conjugates, it was possible to detect an increased resistance of the surfaces against biofouling. Polymer structures which imitate mussel adhesion proteins are an alternative to monomeric catechol derivatives. These are used as a biomimetic adhesive.
With the help of monomeric catechol derivatives, metal surfaces are suitable to be easily functionalised; however, this functionalization unfortunately comes with low durability. This is particularly disadvantageous in the case of heavy material stress such as applications in the dental industry. Although polymer structures allow for an extremely strong connection, they do not allow for a targeted or defined functionalisation of the surface as is desired, by way of example, for implants.
Adamantane is a rigid molecule which comprises three condensed six-member carbocyclic rings. The carbon atoms 1, 3, 5 and 7 of the adamantane are bridgehead atoms. Adamantane derivatives are known and used in medicine and material sciences. When these adamantane derivatives carry identical substituents at three bridgehead positions, they comprise a tripodal arrangement.
US 2006/0063834 A1 describes different adamantane derivatives with tripodal arrangement, methods for their production and their use for pharmaceutical compositions. However, no adamantane derivatives are disclosed which are suitable to functionalise surfaces.
In A Oganesyan, I A Cruz, R B Amador, N A Sorto, J Lozano, C E Godinez, J Anguiano, H Pace, G Sabih, C G Gutierrez: “High Yield Selective Acylation of Polyamines: Proton as Protecting Group”, Org Lett 2007, 9, 4967-4970 describes the selective acylation of polyamines which comprise several identical or similar amine functions. The authors of the paper state that the omnipresence of polyamide bindings in biological molecules converts the selective acylation into an interesting approach for the production of biomimetic molecules. However, no compounds are disclosed comprising substituted 3,4-dihydroxybenzyl groups as ligands of the adamantane which serve to functionalise surfaces.
Methods for the production of rigid tripodal compounds based on adamantane are described in W Maison, J V Frangioni, N Pannier: “Synthesis of Rigid Multivalent Scaffolds Based on Adamantane”, Org Lett 2004, 6, 4567-4569 and in N Pannier, W Maison: “Rigid C3-Symmetric Scaffolds Based on Adamantane”, Eur J Org Chem 2008, 1278-1284 and in K Nasr, N Pannier, J V Frangioni, W Maison: “Rigid Multivalent Scaffolds Based on Adamantane”, J Org Chem 2008, 73, 1058-1060. The production of trivalent adamantane skeletons with ligands comprising catechol units is not disclosed there.
Functionalisations of surfaces with the monomeric derivatives of the catecholamine known up to now comprise the disadvantage that these functionalisations are not sufficiently permanent.